Cryogenic quartz crystal microbalance
Cryogenic quartz crystal microbalance for spacecraft contamination studies
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Post-flight analyses of the crystals from the M0003-14 quartz crystal microbalance experiment
Quartz Crystal Microbalances constructed by QCM Research were flown on the leading and trailing edges of the Long Duration Exposure Facility (LDEF) as one of the sub-experiments of M0003. Response of the crystals coated with 150 A of IN2O3ZnS was recorded during the first 424 days of the mission. A second QCM with crystals coated with 150 A was also flown but not monitored. The flight data and temperature profiles will be presented. After the flight, the QCM's were disassembled and analyzed. The samples included the crystals from the leading and trailing edge samples of both types of coatings along with the reference crystals which were inside the QCM housing. Analyses were performed by scanning electron microscopy, energy dispersive x ray analysis, x ray photoelectron spectroscopy, ion microprobe mass analysis, and reflectance spectroscopy in the infrared and ultraviolet/visible region. The crystals were contaminated predominantly with silicone compounds. The contamination is higher on the leading edge than on the trailing edge, and higher on the exposed crystal than on the reference crystals. No significant differences in composition of the In2O3 crystals were noted. Differences in the reflectance and surface analysis of the Zns crystals will be discussed.
Stuckey, W. K.↗
Post-flight analyses of the crystals from the M0003-14 quartz crystal microbalance experiment
Quartz Crystal Microbalances constructed by QCM Research were flown on the leading and trailing edges of LDEF as one of the sub-experiments of M0003. Response of the crystals coated with 150 A of In2O3 was recorded during the first 424 days of the mission. A second QCM with crystals coated with 150 A of ZnS was also flown but not monitored. After the flight, the QCM's were disassembled and analyzed in The Aerospace Corporation laboratories. The samples included the crystals from the leading and trailing edge samples of both types of coatings along with the reference crystals, which were inside the QCM housing. Analyses were performed by scanning electron microscopy, energy dispersive x-ray analyses, x-ray photoelectron spectroscopy, ion microprobe mass analysis, and reflectance spectroscopy in the infrared and UV/visible regions. The crystals are contaminated predominantly with silicone compounds. The contamination is higher on the leading edge than on the trailing edge and higher on the exposed crystals than on the reference crystals.
Stuckey, W. K.↗
Vacuum Ultraviolet Radiation Desorption of Molecular Contaminants Deposited on Quartz Crystal Microbalances
Recent quartz crystal microbalance measurements made in the Marshall Space Flight Center, Photo-Deposition Facility, for several materials, recorded a significant loss of deposited contaminants when the deposition surface of the microbalance was illuminated by a deuterium lamp. These measurements differ from observations made by other investigators in which the rate of deposition increased significantly when the deposition surface was illuminated with vacuum ultraviolet radiation. These observations suggest that the accelerated deposition of molecular contaminants on optically sensitive surfaces is dependant upon the contaminant being deposited and must be addressed during the materials selection process by common material screening techniques.
Albyn, Keith↗
ATS-6 - Quartz-Crystal Microbalance
The Quartz-Crystal Microbalance Experiment provided data on the possible return of contaminants to the exterior surfaces of the spacecraft. The experiment measures the change in resonant frequency of the crystal due to deposition of material on the surface. There has been no mass accretion corresponding to the firing of hydrazine thrusters to unload the spacecraft momentum wheels. There have been accretions corresponding to the firing of the cesium ion engines.
Rogers, J. F.↗
Cryogenic Quartz Crystal Microbalance
A radiatively cooled Cryogenic Quartz Crystal Microbalance designed to monitor highly volatile contaminants on the shuttle is described. Measurements are made with two 15-MHz microbalances having removable, optically polished sensors mounted in a radiant cooler. One sensor operates below the freezing point of water and monitors contamination including that of water vapor. The second sensor is heated and monitors the contamination background. It provides a reference from which the density of the water vapor cloud enveloping the shuttle is determined. The design incorporates a low-power dissipation oscillator, heaters for ice removal, and a method for attaching second-surface mirrors to the radiator employing an indium type solder instead of a room temperature vulcanizer.
D Mckeown↗
Quartz Crystal Microbalance Operation and In Situ Calibration
Quartz crystal microbalances (QCMs) are commonly used to measure the rate of deposition of molecular species on a surface. The measurement is often used to select materials with a low outgassing rate for applications where the material has a line of sight to a contamination-sensitive surface. A quantitative, in situ calibration of the balance, or balances, using a pure material for which the enthalpy of sublimation is known, is described in this Technical Memorandum. Supporting calculations for surface dwell times of deposited materials and the effusion cell Clausing factor are presented along with examples of multiple QCM measurements of outgassing from a common source.
Albyn, K. C.↗
Temperature-controlled quartz crystal microbalance measurements on Space Transport System (STS-2)
The purpose of the Temperature-Controlled Quartz Crystal Microbalance (TQCM) system on STS-2 was to measure condensible molecular flux in the payload bay of the Space Shuttle as a function of temperature, direction, and time. Five quartz crystal microbalance sensors were located in the IECM to measure molecular adsorption in each of the Orbiter axes, +X (fore), -X (aft), +Y (starboard), -Y (port), and -Z (up, perpendicular to payload bay). The temperature of each sensor was controlled by a thermoelectric device so contamination could be measured as a function of four preset temperatures: +30, 0, -30, and -60 C. When orbital altitude was reached, the TQCM sensors began their orbital measuring cycle routine. The sensors were commanded to 80 C for 30 min, which was used as an initial clean-up. They were then stepped through a program of 2-nr collection periods at each temperature with a 30-min, 80 C period between each collection period. The collection periods progressed in descending order from +30 to -60 C and, then the cycle was repeated. Since the STS-2 orbital phase lasted approximately 53 hrs, the TQCM system completed four cycles and was in the fifth when the mission was terminated.
Fountain, J. A.↗
Quartz Crystal Microbalance (QCM) monitor of contamination for LES-8/9
A Quartz Crystal Microbalance (QCM) was used to monitor condensable contamination during the launching of two Lincoln Laboratory Experimental Satellites--LES-8 and LES-9. The QCM was installed on the dispenser truss and measured contamination by means of a frequency shift of a quartz crystal oscillator. By using a special crystal cut and a second reference quartz crystal, the sensor had extreme sensitivity and remarkable temperature independence. A 1-Hz frequency shift, which corresponds to 3.5 x 10 to the -9th power g/sq cm was resolved by the flight instrumentation.
Lynch, J. T.↗
Thermogravimetric Analysis Utilizing Quartz Crystal Microbalances
Poster covering a section of Thermogravimetric Analysis using a Quartz Crystal Microbalance, highlighting drop casting as a method.
Quarshie, Joseph Nii Ofori↗
Quartz crystal microbalance use in biological studies
Design, development, and applications of quartz crystal microbalance are discussed. Two types of crystals are used. One serves as reference and other senses changes in mass. Specific application to study of bacterial spores is described.
Green, R. H.↗
Quartz crystal microbalance contamination monitors on Skylab: A quick look analysis
Six quartz crystal microbalance contamination monitors were flown on Skylab to monitor the deposition of material from spacecraft outgassing and from the rendezvous and docking maneuvers of the Command/Service Module. This report contains a quick-look analysis of the data from these units during the unmanned and manned portions of SL2.
Naumann, R.↗
Insitu Calibration of Quartz Crystal Microbalances
Computer models that predict the rate at which molecular contamination will deposit on optical surfaces typically use outgassing source terms, measured with quartz crystal microbalances, as a basis for the prediction. The American Society of Testing and Materials, Standard Test Method for Contamination Outgassing Characteristics of Spacecraft Materials (Method E-1559), is probably the best know technique used by the aerospace community to measure the outgassing rates or source terms of materials. A simple method for the insitu calibration of quartz crystal microbalances, based on the heat of enthalphy of Adipic Acid, has been developed and demonstrated by the Marshall Space Flight Center, Environmental Effects Group. The calibration has been demonstrated over a sample temperature range of 25 to 66 degrees Celsius and deposition rates of 7 x 10 (exp -11) grams/cm(sup 2)-s and greater, for several measurement system configurations. This calibration technique is fully compatible with the American Society for Testing and Materials, Method E-1559, as well as other methodology. The calibration requires no modification of outgassing facilities employing an effusion cell and does not degrade the performance or function of typical vacuum systems.
Albyn, Keith↗
Data from a synchronous altitude satellite quartz crystal microbalance monitor
Results of one year's operation in orbit of the Quartz Crystal Microbalance Monitor on the ATS-6 satellite are presented. The data indicate a general decreasing trend for the first four and one-half months in orbit. At that time, a sudden increase in beat frequency occurred; this correlates in time with the firing of the North Cesium Ion Engine. A general increase in beat frequency is evidenced since that time. Laboratory tests conducted to investigate the phenomenon are described.
Rogers, J. F.↗
Some Sources of Contaminants in the Shuttle Bay Measured with Temperature-Controlled Quartz Crystal Microbalances (TQCM)
The sources of molecular deposits on a Temperature-Controlled Quartz Crystal Microbalance (TQCM) attached to the shuttle bay wall at some distance from the payload and pointing out of the bay have been investigated. Explored as possible sources are: (1) the outgassing of the shuttle tiles treated with the water proofing di-methyl-ethoxy-silane (DMES) compound, scattered back by the ambient molecules into the bay; (2) The ambient scattered return flux of the outgassing, from the RTV 560 silicone which is used as the adhesive for the tiles; (3) the ambient scattered return flux of the payload outgassing; (4) the return C, flux from outgassing source originating near, below, or adjacent to the package containing the TQCM; and (5) the self-scattering of venting plumes and outgassing above the monitor package depositing on the TQCM. In all of these sources, the magnitudes of the outgassing, of the leakage rates, and venting had to be estimated in the absence of data. The resulting analyses which can be useful for similar investigations, indicates that the outgassin- from the tiles, the RTV, the payloads, or the shuttle may not have been the sources of the deposit (about 1 micro g/cm(sup 2) during a the period from bay door opening and payload release from the bay). It appears more probable that the origin is the self- and/or ambient-scattered return fluxes originating near, below, or internal to the monitor package.
Scialdone, John J.↗
Data analysis for lidar and quartz crystal microbalance systems
Results are presented of the analysis of data taken on the stratospheric aerosol, using lidar, Quartz Crystal Microbalance (QCM), and the SAGE and SAM II satellite systems. The main objective of the work reported has been to use the data, taken with the NASA-LaRC instruments to study the stratospheric effects of volcanic eruptions during the period between the launch of the SAGE and SAM II satellite systems and October 1980. Four significant volcanic eruptions, for which data are available, occurred during this period--Soufriere, Sierra Negra, Mt. St. Helens, and Ulawun. Data on these have been analyzed to determine the changes in stratospheric mass loading produced by the eruptions, and to study the dispersion of the newly injected material.
Kent, G. S.↗
The Response of a Quartz Crystal Microbalance to a Liquid Deposit
A theory was developed for predicting the loss of response of a QCM (Quartz Crystal Microbalance) to a liquid deposit due to viscous effects in the deposit. The loss of response is expressed by a response factor, equal to the response of the QCM to a liquid film divided by its response to a solid film of the same mass per unit area. The theory assumes a droplet-type deposit morphology, and considers the influence of droplet distribution parameters. Experiments were conducted to examine the validity of the theory, using DC 704 silicone oil as the subject deposit material. Experiments were made in two series: one with constant deposit mass and variable temperature, the other with variable deposit mass and constant temperature. Interpretation of the data using the theory has enabled information on droplet area coverage and number density to be deduced.
Glassford, A. P. M.↗
The calibration of the quartz crystal microbalance cascade impactor using the berglund-liu monodisperse aerosol generator for aerosol studies in the atmosphere
The Quartz Crystal Microbalance was calibrated and its response to particle size and mass concentration was determined.
Matthews, N.↗